Thermodynamic study of phase transfer of precipitates on SiC whisker reinforced glass ceramics.
Physiochemical properties of glass ceramics in weakly buffered, supersaturated, metastable calcium and phosphate solution were studied. Formations of calcium phosphate precipitates were also analyzed thermodynamically. All biomaterials examined here showed primarily dissolution process and subsequent nucleation. Dissolution was enhanced in those which contained Na2O and/or SiC. The dissolution of calcium and phosphate ions from biomaterials and subsequent nucleation of calcium phosphate salts after induction time resulted in a stable equilibrium having solubility characteristics similar to octacalcium phosphate (OCP). The most soluble material, CPSN-SiC, showed an initial transient equilibrium with amorphous calcium phosphate (ACP). From above results, calcium phosphate ceramics had certain driving force of its own which kept the equilibrium of solution to OCP thermodynamically for 7 days. Despite the favorable solubility equilibrium attained, there still remain problems for clinical application.
Imai
K
K
Department of Oral Biochemistry, Kanagawa Dental College, Japan.
Yuge
T
T
Ito
S
S
Kawase
T
T
Saito
S
S
D001672:Biocompatible Materials; D002118:Calcium; D002130:Calcium Phosphates; D002244:Carbon; D017554:Carbon Compounds, Inorganic; D002516:Ceramics; D055598:Chemical Phenomena; D011232:Chemical Precipitation; D002627:Chemistry, Physical; D005898:Glass; D006863:Hydrogen-Ion Concentration; D010710:Phosphates; D012825:Silicon; D017655:Silicon Compounds; D012995:Solubility; D012996:Solutions; D013816:Thermodynamics
D001672:Biocompatible Materials; D002130:Calcium Phosphates; D017554:Carbon Compounds, Inorganic; D010710:Phosphates; D017655:Silicon Compounds; D012996:Solutions; C519480:amorphous calcium phosphate; D002244:Carbon; D002118:Calcium; C022088:silicon carbide; D012825:Silicon